Distribution of particulate material

ABSTRACT

An apparatus for distributing particulate material includes a feeder having a charging inlet and a discharge outlet duct having converging walls. Coaxially aligned with the discharge outlet duct is a deflector including a first spreader having diverging outer walls, and a second spreader contiguous with the diverging walls of the first spreader and having diverging walls of an angular inclination to the direction of flow of the particulate material greater than that of the first spreader. The charging inlet may have attached thereto an extension and an expansion chamber into which a feed pipe projects, the expansion chamber and the feed pipe being external to a receiving vessel. The particulate material may be fed into the feeder entrained in air. The material leaving the second spreader is uniformly distributed and may form a hollow curtain of uniformly distributed particulate material. The curtain may fall into a spray mixing vessel, and a circular baffle may contain the curtain. The baffle may carry fins and divide the curtain to pre-determined separate streams. The streams may be led away for use elsewhere, and streams may be formed at the discharge end of the second spreader rather than by the use of fins.

DESCRIPTION

This invention relates to an apparatus for and a method of distributingparticulate material. In one application of the invention the materialis formed into a curtain that flows into a spray mixing vessel. Inanother the material may be divided into a number of separate streams.

According to the invention, there is provided an apparatus fordistributing particulate material including an expansion chamber forreceiving particulate material extrained in air and effecting areduction in the speed of the air in which the particulate material isentrained, a feeder having a charging inlet which communicates with theexpansion chamber and a discharge outlet duct, the discharge outlet ducthaving converging walls, a deflector to deflect particulate materialreceived from the expansion chamber and the feeder, the deflectorincluding a first conical spreader co-axially aligned with the dischargeoutlet duct and having walls which diverge away from the dischargeoutlet duct, a second conical spreader continguous with the divergingwalls of the first conical spreader and having diverging walls of anangular inclination to the direction of flow of the particulate materialgreater than that of the first conical spreader so that, in use, thedischarge of particulate material from the second conical spreader is inthe form of a hollow cylindrical curtain of uniformly distributedparticulate material.

According to the present invention, there is also provided an apparatusfor distributing particulate material including an expansion chamber forreceiving particulate material entrained in air and effecting areduction in the speed of the air in which the particulate material isentrained, a feeder having a charging inlet which communicates with theexpansion chamber and a discharge outlet duct, the discharge outlet ducthaving converging walls, a deflector to deflect particulate materialreceived from the expansion chamber and the feeder, the deflectorincluding a first conical spreader co-axially aligned with the dischargeoutlet duct and having walls which diverge away from the dischargeoutlet duct, a second conical spreader continguous with the divergingwalls of the first conical spreader and having diverging walls of anangular inclination to the direction of flow of the particulate materialgreater than that of the first conical spreader so that, in use, thedischarge of particulate material from the second conical spreader is inthe form of a hollow cylindrical curtain of uniformly distributedparticulate material which is received by baffle means that divides thematerial into streams in which the rates of flow have a predeterminedrelationship to each other.

According to the invention there is further provided a method ofdistributing particulate material including entraining the particulatematerial in air, reducing the speed of the flow of air in which theparticulate material is entrained by passing the entrained particulatematerial through an expansion chamber, charging a feeder with theentrained particulate material, the feeder communication with theexpansion chamber, discharging the particulate material from the feederand directing the flow of particulate material onto a deflector so thata hollow cylindrical curtain of uniformly distributed particulatematerial is formed leaving the deflector.

The single FIGURE of the drawing is a vertical sectional view of adistributor for a particulate material.

The single FIGURE of the drawings in which an apparatus for distributingparticulate material includes a cylindrical feeder 2 having an open top4 forming a charging inlet, the periphery of which is surrounded by anexternal flange 6. Spaced apart from the charging inlet 4 and axiallyaligned therewith is a circular aperture 8 surrounded by an externalperipheral flange 10, the aperture 8 communicating with an axiallyaligned discharge outlet duct 12 at a lower end portion of the feeder 2.The discharge outlet duct 12 is frusto-conical in shape having at anupper end portion thereof an external peripheral flange 14 which isattached to the external peripheral flange 10 of the circular aperture.Inner walls of the discharge outlet duct 12 converge and extend towardsa lower circular outlet 16 from whose periphery extends a dependingcylindrical rim 18.

Interposed between the charging inlet 4 and the discharge outlet duct 12are a plurality of support members 20 each having spaced apart strutswhich radiate out from a central boss. Each boss is drilled to provide abore which is aligned with a central axis of the feeder 2. The free endsof the struts are attached to the inner walls of the feeder 2.

A shaft 22 extends through the bores of each of the central bosses ofthe support members 20 such that the shaft 22 is axially aligned withthe central axis of the feeder 2. The length of the shaft 22 is suchthat a lower end portion of the shaft projects beyond the lower circularoutlet 16 of the discharge outlet duct 12 and such that an upperthreaded end portion thereof extends beyond a support member 20 adjacentthe charging inlet 4. The support member 20 adjacent the charging inlet4 has a threaded bore and the threaded portion of the shaft 22 is matedwith the threaded bore in the support member and secured by a lock nut24. The length of the shaft 22 projecting beyond the lower circularoutlet 16 may be altered by securing the upper end portion of the shaft22, releasing the lock nut 24, adjusting the length of the shaft 22projecting beyond the lower circular outlet 16, and then re-securing thelock nut 24.

Attached to the lower end portion of the shaft 22 is a deflector 26having outer surfaces with diverge away from the discharge outlet duct12. The deflector 26 includes a conical spreader, co-axially alignedwith the discharge outlet duct 12, having an upper portion 28 projectinginto the discharge outlet duct 12 so that an annular space existsbetween the outer surface of the spreader and the inner wall of thedischarge outlet duct 12, and a lower portion 30 remote from the feeder2. The lower portion 30 of the spreader has an angular inclination tothe direction of flow of the particulate material greater than that ofthe upper portion of a greater radius thereto such that the lowerportion 30 is flared with respect to the upper portion 28.

Connected to the peripheral flange 6 surrounding the charging inlet 4 ofthe feeder 2 is a cylindrical extension 32 having at an upper endportion thereof remote from the charging inlet 4 a circular inlet 34.The circular inlet 34 is frusto-conical in shape having at an upperportion thereof an external peripheral flange 36. Inner walls of thecircular inlet 34 converge to form an inlet axially aligned with thecharging inlet 4 and the discharge outlet duct 12.

Attached to the peripheral flange 36 surrounding the circular inlet 34of the extension 32 is an expansion chamber 38 having a substantiallycylindrical shape with which is bent to form a 90° bend. The expansionchamber 38 includes a lower cylindrical portion 40 of a similar diameterto that of the extension 32 and feeder 2, and an upper frusto-conicalportion 42 whose internal diameter decreases progressively from thelower portion 40 toward an inlet 44 remote from the lower portion 40.The periphery of the inlet is surrounded by an external flange 46.

Attached to the external flange 46 of the inlet 44 of the expansionchamber 38 is a feed pipe 48.

The feeder 2 and associated deflector 26 are inserted into an aperture50 in an upper portion of a vessel 52 such that the deflector 26 anddischarge outlet duct 12 project into the vessel 52 and such that thecharging inlet 4 of the feeder 2 is external to the vessel 52. A portionof the feeder 2 adjacent the aperture 50 in the upper portion of thevessel 52 is strengthened by webs 54 which extend from the externalwalls of the feeder and are attached to an outer surface of the vessel52.

Attached to an upper inner surface of the vessel 52 and to theperipheral flange 14 of the discharge outlet duct 12 is a baffle 56 inthe form of a plate 58 having a depending cylindrical skirt 60 whichsurrounds and is spaced apart from the deflector 26 and the dischargeoutlet duct 12.

In operation, particulate material entrained in air is fed into the feedpipe 48 where on entry into the expansion chamber 38 the particulatematerial is directed by the shape of the upper portion 42 onto the innerwalls of the lower portion 40 where a reduction in the speed of flow ofthe air in which the particulate material is entrained takes place.

The particulate material is then pneumatically conveyed into thecircular inlet 34 of the extension 32 where due to the shape of thecircular inlet 34 the particulate material is channelled away from theinner walls and caused to flow in a uniformly distributed streamadjacent the central axis of the extension 32.

The stream of uniformly distributed particulate material enters thecharging inlet 4 of the feeder 2, flows past the support members 20 andthe shaft 22 towards the discharge outlet duct 12 where due to the shapeof the inner walls of the discharge outlet duct 12 the particulatematerial from the inner walls of the feeder, deflected by impinging onthe support members 20 and the shaft 22, is channelled away and formedinto a stream of uniformly distributed particulate material. The streamis then conveyed onto the upper portion 28 of the spreader where onimpinging on the outer surface thereof the stream is directed radiallyoutwardly then further spread out by impinging upon the lower portion ofthe spreader. The material leaving the portion 30 is uniformlydistributed and, impinging on the cylindrical skirt 60, will constitutean annular curtain of uniformly distributed particulate material.

The dimensions of the curtain, particularly the diameter thereof, may bealtered firstly by adjusting the position of the deflector 26 inrelation to the discharge outlet duct 12 of the feeder for alteration ofthe internal diameter, and secondly by altering the radius of thecylindrical skirt 60 for alteration of the external diameter.Additionally the dimensions of the curtain may be altered by alteringthe velocity of the air in which the particulate material is conveyed.

It should also be appreciated that the feed pipe 48 may be fed directlyinto the charging inlet 4 of the feeder 2.

It should also be appreciated that the particulate material may be fedinto the apparatus without being entrained in air.

It should further be appreciated that the upper portion 28 and the lowerportion 30 of the conical spreader may be constructed from separatecastings and be connected together such that the outer surfaces of thelower portion 30 is contiguous with the outer surface of the upperportion 28.

The vessel 52 may be a spray mixing vessel in which the material in theuniform curtain will be mixed with a liquid.

Since the material leaving the lower portion 30 is uniformlydistributed, that may serve as the source of a plurality of streams ofparticulate material having a pre-determined ratio of rates of flow. Forinstance, to divide the material leaving the portion 30 into eight equalstreams, the inner surface of the skirt 60 may be provided with eightsimilar, radially extending and equiangularly spaced fins, of which twoare indicated in broken lines at 62. There will be equal rates of flowbetween each two adjacent pairs of fins and the material may be led awayfrom the bottom of the pair of fins to a point of use. It is envisagedthat the particulate material may be fuel, so that eight burners couldbe equally supplied from a single source of fuel.

As an alternative, material leaving the portion 30 may dischargedirectly into the inlet ends of ducts through which it passes to thepoints of use. The portion 30 might be provided with a downwardextension that is provided with grooves that lead to the inlet ends ofthe ducts.

The material leaving the portion 30 may be divided not only a number ofequal parts but into parts of different sizes having a pre-determinedrelation to each other.

We claim:
 1. An apparatus for distributing entrained particulatematerial including an expansion chamber for receiving particulatematerial entrained in air and effecting a reduction in the speed of theair in which the particulate material is entrained, a means forchanneling the entrained particulate material, having converging walls,which communicates with the expansion chamber to produce a flow ofuniform distribution, a mixing vessel, a feeder located in the mixingvessel and having a charging inlet which communicates with thechannelling means and receives particulate material having a flow ofuniform distribution therefrom and a discharge outlet duct, thedischarge outlet duct having converging walls, a deflector to deflectparticulate material received from the feeder, the deflector including afirst conical spreader co-axially aligned within the discharge outletduct of the feeder and having walls which diverge away from thedischarge outlet duct, a second conical spreader continguous with thediverging walls of the first concial spreader and having diverging wallsof an angular inclination to the direction of flow of the particulatematerial greater than that of the first conical spreader, and a circularbaffle positioned within the mixing vessel and spaced apart from andsurrounding the first and second spreaders so that, in use, thedischarge of particulate material from the second conical spreader is inthe form of a hollow cylindrical curtain of uniformly distributedparticulate material.
 2. An apparatus for distributing entrainedparticulate material including an expansion chamber for receivingparticulate material entrained in air and effecting a reduction in thespeed of the air in which the particulate material is entrained, a meansfor channelling the entrained particulate material, having convergingwalls, which communicates with the expansion chamber to produce a flowof uniform distribution, a mixing vessel, a feeder located in the mixingvessel and having a charging inlet which communicates with thechannelling means and receives particulate material therefrom having aflow of uniform distribution and a discharge outlet duct, the dischargeoulet duct having converging walls, a deflector to deflect particulatematerial received from the feeder, the deflector including a firstconical spreader co-axially aligned within the discharge outlet duct ofthe feeder and having walls which diverge away from the discharge outletduct, a second conical spreader continguous with the diverging walls ofthe first conical spreader and having diverging walls of an angularinclination to the direction of flow of the particulate material greaterthan that of the first conical spreader and a circular baffle meansprovided with a plurality of radically inwardly, projecting fins whichbaffle means is positioned within the mixing vessel and spaced apartfrom and surrounding the first and second conical spreaders so that, inuse, the discharge of particulate material from the second conicalspreader is in the form of a hollow cylindrical curtain of uniformlydistributed particulate material which is received by the baffle meanssuch that the material is divided into streams in which the rates offlow have a predetermined relationship to each other.
 3. A method ofdistributing entrained particulate material including entraining theparticulate material in air, reducing the speed of the flow of air inwhich the particulate material is entrained by passing the entrainedparticulate material through an expansion chamber, channelling theentrained particulate material through a convergent duct prior tocharging into a feeder to produce a flow of uniform distribution intothe feeder, charging the feeder with the flow of uniformly distributedentrained particulate material, the feeder being positioned within amixing vessel, discharging particulate material from the feeder,controlling the discharge of particulate material from the feeder,directing the flow of particulate material onto a deflector so that ahollow cylindrical curtain of uniformly distributed particulate materialis formed leaving the deflector, and limiting the diameter of the hollowcylindrical curtain leaving the deflector by positioning a circularbaffle within the mixing vessel spaced apart from and surrounding thedeflector.